Nigella sativa L. belongs to the family of Ranuculaceae, which is known as food flavouring agents, food preservatives as well as health-promoting ingredients since few thousands years ago. Generally, Nigella sativa seeds contain more than 30% of fixed oil and 0.40% to 0.45% of volatile oil. Nigella sativa oil is considered as one of the excellent functional edible oil due to its advantage role in human nutrition as well as diseases prevention and treatment.
Thymoquionone (TQ) is the major bioactive component (18.4% to 24%) in Nigella sativa volatile oil. Many pharmacological researches reported that Nigella sativa oil and its bioactive compound, TQ possesses multiple health-beneficial activities, which include anti-tumor, anti-inflammatory, anti-bacterial, anti-diabetic, anti-hypertensive, hyperglycemic, anti-oxidatative and immuno-modulation activities.
Due to its multiple health benefits, extraction of TQ from Nigella sativa seeds is of prime importance and thus has received continuous attention from researchers and nutraceutical industry worldwide recently. However, the present methods (solvent extractions and hydro distillation) that are used in the oil extraction of Nigella sativa seeds are not only time-consuming, costly and environmental hazardous, it also imposes a threat to consumers' health if the organic solvents are not completely removed from the extractives. In this scenario, supercritical carbon dioxide fluid extraction (SFE) seems to be a better alternative for Nigella sativa seeds extraction. Advantageously, SFE offers the usage of non-toxic, non-explosive, environmental friendly, cost effective, time saving and selectivity-adjustable solvent (supercritical carbon dioxide fluid) in the extraction process. Further more, it also enables the oil extraction to be carried out under low temperature and oxygen-free condition. This feature is very crucial in the extraction of bioactive compounds that are highly susceptible to oxidative degradation, for instance TQ. On the other hand, simultaneous fractionation by using SFE enables the concentration of targeted bioactive compound such as TQ to be conducted in a solvent-free as well as time and cost saving manner.
The objective of this invention is to develop an extraction procedure to obtain Nigella sativa seeds oil and fractions that are high in bioactive compounds (such as TQ) and anti-oxidative activity through SFE extraction and fractionation.